stonyiron

Stonyiron, commonly referred to as stony-iron meteorites, is a class of meteoritic material defined by a mixed silicate and nickel-iron composition. This combination places stonyiron between stony meteorites and iron meteorites in the traditional classification.

The best-known subgroups are pallasites, where olivine-rich crystals are embedded in a nickel-iron alloy, and mesosiderites, which show a more interwoven mixture of metal and silicate. Textures range from lamellar to brecciated forms, and individual specimens can exhibit highly variable mineralogy.

Formation is interpreted as arising in the cores–mantle boundary regions of differentiated parent bodies, with metal and silicate phases mingling before final cooling. This records planetary differentiation and collisional history in the early solar system.

Compositionally, the metal component is a nickel-iron alloy (containing kamacite and taenite), while the silicate portion includes olivine and pyroxene, along with accessory minerals such as troilite and chromite. The combination yields high density and a distinctive metallic luster, and they are typically magnetic.

Occurrence and significance: Stonyiron meteorites are relatively rare among meteorite finds and are studied for insights into core formation, mantle processes, and early solar-system dynamics. They have no commercial metallurgical use, but are highly valued by researchers and collectors for their unique textures and cosmochemical information.

Etymology: The term reflects the blended stone-and-iron composition.